Comparison of findings in patients with versus without atrial fibrillation just before isolated mitral valve replacement for rheumatic mitral stenosis (with or without associated mitral regurgitation).

Among 104 patients with mitral stenosis (MS) severe enough or symptomatic enough to warrant mitral valve replacement (MVR), 47 (45%) had atrial fibrillation (AF) and 57 (55%) had sinus rhythm just before the MVR. Of the latter 57 patients, 21 (37%) had had previous episodes compatible with AF. If these 21 patients were included with the 47 patients with electrocardiographic documentation of AF just before MVR, a total of 68 (65%) would have had > or =1 presumed episodes of AF before MVR. The 13 patients with previous mitral commissurotomy had a frequency of AF similar to that of the 91 whose first operation was MVR. Compared with the patients with sinus rhythm just before MVR, those with AF had more heart failure (functional class III or IV preoperatively, 79% vs 62%), larger left atria (6.0 vs 5.2 cm), larger left ventricles in peak systole (4.0 vs 2.6 cm), and more had 2 or 3 coronary arteries narrowed >50% in diameter (23% vs 10%).